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BIOPROSPEK KITOSAN DARIPADA CENGKERANG KETAM SEBAGAI PENGGUMPAL SEMULAJADI UNTUK RAWATAN AIR
No full textDecoding the influence of bacterial community structure and algicidal bacteria in a Karenia longicanalis bloom event
No full textHarmful algal blooms (HABs) have been increasing in frequency and expanding their ranges on coastlines worldwide in recent decades. Algicidal bacteria play a pivotal role in eliminating HABs, yet the characteristics of bacterial communities and their algicidal activity during a Karenia longicanalis bloom remain poorly understood
Biotechnological potential of Ulva ohnoi epiphytic bacteria: enzyme production and antimicrobial activities
No full textSeaweed surfaces harbor diverse epibiotic bacterial communities with functions
related to morphogenesis, host health, and defense. Among seaweed
holobionts, culturable strains can represent innovative sources of bioactive
compounds and enzymes. The global industrial demand for microbial enzymes
is continually growing in order to improve certain manufacturing processes with
new perspectives of industrial exploitation. In this regard, the present study
focuses on the enzymatic production and the antimicrobial activities of
culturable epibiotic bacteria of Ulva from the Tunisian coast. Culturable
associated bacteria were isolated and molecular identification was realized by
16S rRNA gene sequencing. For each strain, eight enzymatic activities were
investigated: amylase, hemolysis, DNase, cellulase, lecithinase, lipase, gelatinase,
and chitinase. The antimicrobial activity of Ulva-associated bacteria was
evaluated against seven pathogenic bacteria, Escherichia coli, Vibrio
anguillarum, Vibrio alginoliticus, Pseudomonas aeruginosa, Aeromonas
hydrophila, Salmonella typhymurium, and Staphylococcus aureus, and one
yeast, Candida albicans. The antibiotic resistance of isolated strains was
determined for 15 commonly used antibiotics. The phylogenetic analysis
revealed that the isolates belonged to Alphaproteobacteria (3) ,
Gammaproteobacteria (5), Actinobacteria (3), and Firmicutes (4) phyllum. The
majority of the isolates (66%) produced simultaneously more than one enzyme.
Hemolysis was produced by 46.6% of isolates, while DNase was produced by
33% of strains. On the other hand, 13% of strains produced lecithinase, gelatinase,
cellulase, and lipase. No chitinase was produced by the isolated bacteria. In
addition, 60% of isolates displayed antimicrobial activity against at least one
pathogenic strain. All Ulva ohnoi-associated bacteria were resistant to at least
seven commonly used antibiotics. These results highlighted the occurrence of
several enzymatic activities within Ulva-associated bacteria that can have
potential uses in the industrial sector
Jaws from the deep: biological and ecological insights on the kitefin shark Dalatias licha from the Mediterranean Sea
No full textDue to their late maturation, extreme longevity, low fecundity and slow growth
rates, deep-sea Chondrichthyes are extremely vulnerable to human impacts.
Moreover, assessing the impact of deep-sea fisheries is difficult, as many species
(including sharks) are part of the bycatch and are often discarded at sea, and/or
landed under generic commercial-species codes. The lack of this information on
fishery data sets and the limited availability of species-specific life history data
make challenging the management of deep-sea Chondrichthyes. The kitefin
shark Dalatias licha is a cosmopolitan elasmobranch, mainly found on
continental and insular shelf-breaks and slopes in warm-temperate and
tropical waters. This species is a common by-catch of the deep-sea trawling,
considered as ?Endangered? by the IUCN Red List for all European waters,
Mediterranean Sea included. Here we present the results of a study based on a
total of 78 specimens of kitefin shark collected over 3 years in the Ligurian Sea
(NW Mediterranean) as by-catch from deep-water fisheries. Total length ranged
from 380 to 1164 mm, and individual weight ranged from 198 to 8000 g.
Immature and mature individuals showed a sex ratio dominated by males.
Adult males were observed throughout the year, while mature females were
observed only in spring-summer. These data lead to hypothesise a spatial
segregation between genders
Local scale extreme low pH conditions and genetic differences shape phenotypic variation in a broad dispersal copepod species
No full textExtreme low pH events in estuaries and upwelling areas can modulate the
phenotypic and genetic diversity of natural populations. To test this hypothesis,
we explored the linkage between local scale extreme low pH events, genetic
diversity, and variation in fecundity-related traits (body size, egg size, and egg
production rate) in the broad-dispersal copepod Acartia tonsa. We assessed
genetic and phenotypic characteristics of populations by contrasting extreme
low pH environments (upwelling and temperate estuary) in the coastal Southeast
Pacific, under natural and experimental conditions. These populations showed
significant genetic differentiation with higher diversity in mitochondrial and
nuclear loci (encoding mtCOI and 18S rRNA) in the estuarine population.
Copepods from this population are exposed to more frequent extreme low pH
events (< 7.7), and the adult females exhibit consistent phenotypic variation in
body size, egg size, and egg production rate across different cohorts.
Experimental acclimation to extreme low pH conditions revealed no significant
differences in fecundity-related traits between A. tonsa populations. Although
these results partially support our hypothesis, the experimental findings suggest
other drivers might also influence phenotypic di fferences in the
local environments
Land-Use Optimization and Allocation for Saltwater Intrusion Regions: A Case Study in Soc Trang Province, Vietnam
No full textLand-use planning plays an important role in agricultural development. However, the
tools used to support planners in proposing land-use planning solutions are lacking, especially
when considering saltwater intrusion conditions in coastal regions. In this study, optimization is
applied by analyzing land use in developing solutions for agricultural land-use planning, wherein
a multi-objective optimization model is developed to optimize land-use area, including land-use
allocation, and taking into account socioeconomic and environmental factors. The model was applied
to three districts of Soc Trang province, Vietnam (Long Phu, My Xuyen, and Tran De), representing
three ecological regions of salt water, brackish water, and fresh water in the Mekong Delta of
Vietnam. The results are shown for the implementation of two multi-objective optimization scenarios
(in terms of profit, labor, environment benefits, and risk reduction) as follows: (i) multi-objective
optimization of agricultural land use until 2030 under normal conditions; (ii) optimizing agricultural
land use until 2030 under climate change conditions similar to the 2016 drought and saltwater
intrusion phenomenon in the Mekong Delta. The results demonstrate that the second scenario is the
preferred option for implementing land-use planning thanks to the balance between good profits and
minimizing economic and environmental risk. Land allocation was carried out by taking into account
the factors of household economics, the influence of adjacent production types, local traffic, and canal
systems to allocate areas toward ensuring optimal land use. This process, involving a combination of
land-use optimization and spatial allocation, can help planners to improve the quality of agricultural
land-use planning
